Splice mechanism for a packaging assembly

Abstract

A splice mechanism ( 100 ) for a packaging assembly ( 10 ), the packaging assembly ( 10 ) including: a former shoulder ( 12 ); a controller ( 14 ); a film drive ( 16 ) controlled by the controller ( 14 ) for feeding a film ( 112 ) at a film speed to the former shoulder ( 12 ) to form a tubular film ( 22 ) moving in a film direction ( 20 ); a sealing device ( 24 ) to seal the tubular film ( 22 ) in a first sealing direction ( 26 ), the first sealing direction ( 26 ) being parallel to the film direction ( 20 ); a set of jaws ( 28 ) controlled by the controller ( 14 ) and movable at a jaw speed to engage and seal the tubular film ( 22 ) in a second sealing direction ( 30 ) to form a first seal ( 32 ) and a second seal ( 34 ) in each bag, thereby forming a closed bag ( 36 ), the splice mechanism ( 100 ) including: an active film roll ( 110 ) from which film ( 112 ) is drawn to be fed to the former shoulder ( 12 ) by the film drive ( 16 ); a second film roll ( 120 ) having film ( 122 ) for feeding to the former shoulder ( 12 ); a film roll holder ( 130 ) holding the active film roll ( 110 ) and the second film roll ( 120 ) such that film ( 112 ) from the active film roll ( 110 ) extends along a film path ( 140 ) to the former shoulder ( 12 ) and the second film roll ( 120 ) is accessible; a splice roller ( 150 ) against which film ( 122 ) from the second film roll ( 120 ) is placed, the film ( 122 ) having a film end ( 124 ), the film end ( 124 ) having an adhesive ( 126 ), the splice roller ( 150 ) being movable between a free position, wherein the film path ( 140 ) is unimpeded by the splice roller ( 150 ), and a splice position, wherein the film path ( 140 ) is tangential to the splice roller ( 150 ) at a splice point ( 142 ) on the film path ( 140 ).

The invention claimed is: 
     
         1 . A splice mechanism for a packaging assembly, the packaging assembly including:
 a former shoulder;   a controller;   a belt drive controlled by the controller for feeding a film at a film speed to the former shoulder to form a tubular film moving in a film direction;   a sealing device to seal the tubular film in a first sealing direction, the first sealing direction being parallel to the film direction; and   a set of jaws controlled by the controller and movable at a jaw speed to engage and seal the tubular film in a second sealing direction to form a first seal and a second seal in each bag, thereby forming a closed bag, the splice mechanism comprising:   a film roll holder for holding an active film roll from which film is drawn to be fed to the former shoulder and a second film roll having film for feeding to the former shoulder, wherein film from the active film roll extends along a film path to the former shoulder and the second film roll is accessible; and   a splice roller against which film from the second film roll is placed, the film having a film end, the film end having an adhesive, the splice roller being movable between a free position, wherein the film path is unimpeded by the splice roller, and a splice position, wherein the film path is tangential to the splice roller at a splice point on the film path;   wherein the splice mechanism further includes a first pinch drive mechanism locatable along the film path between the active film roll and the former shoulder, the first pinch drive mechanism having a first pinch roller and a second pinch roller positioned such that the first pinch roller and the second pinch roller engage and draw the film from the active film roll at the film speed,   wherein, when the splice roller is in the splice position, the splice roller and the first pinch roller are adjacent each other such that the film of the active film roll and the film of the second film roll is engaged by the splice roller and the first pinch roller, and   wherein, when the splice roller is in the splice position, the first pinch drive mechanism drives the film opposite the film direction.   
     
     
         2 . The splice mechanism of  claim 1 , wherein the splice mechanism further includes:
 a film calendar locatable between the active film roll and the former shoulder having a set of stationary rollers, and a set of movable rollers that are mounted on a movable calendar arm, with the film path rounding the set of stationary rollers and the set of movable rollers alternatingly such that movement of the calendar arm along an arm path changes a length of the film path through the film calendar, and   a second pinch drive mechanism locatable between the film calendar and the former shoulder, the second pinch drive mechanism having a first pinch roller and a second pinch roller positioned such that the first pinch roller and the second pinch roller engage and draw the film from the film calendar,   wherein, when the splice roller is moved to the splice position, the calendar arm moves along the arm path to reduce the length of the film path through the film calendar as film is fed to the former shoulder, such that the film speed through the second pinch drive mechanism is higher than the film speed at the splice point.   
     
     
         3 . The splice mechanism of  claim 2 , wherein the splice roller is further movable to a load position between the free position and the splice position, and
 the film includes a set of regularly spaced registration marks and the splice mechanism further includes:   a splice actuator to move the splice roller between the load position and the splice position;   a registration mark sensor locatable between the film calendar and the former shoulder, the registration mark sensor configured to provide a registration signal to the controller, the registration signal being indicative of whether a registration mark of the set of regularly spaced registration marks is present on the active film at a sensor point on the film path adjacent the registration mark sensor;   a film roll spindle mounted on the film roll holder for supporting the active film roll;   a brake associated with the film roll spindle to resist the drawing of film from the active film roll; and   a speed sensor associated with the film roll spindle configured to provide a spindle speed signal to the controller, the spindle speed signal being indicative of a rotational speed of the active film roll,   wherein the controller is configured to:
 determine when the active film roll has run out of film by determining whether the spindle speed signal drops below a predetermined threshold; 
 determine the film path between the sensor point and the splice point based on at least predetermined information on the film path; and 
 determine a number of registration marks on the active film between the splice point and a film end of the film previously drawn from the active film roll; 
 operate the splice actuator to move the splice roller from the load position to the splice position when the number of registration marks between the splice point and the film end is below a predetermined threshold. 
   
     
     
         4 . The splice mechanism of  claim 3 , wherein the film calendar further includes an arm sensor adapted to provide an arm signal to the controller, the arm signal being indicative of a position of the movable calendar arm along the arm path, and
 wherein the controller is configured to determine the film path between the registration sensor point and the splice point based on at least the calendar arm position along the arm path.   
     
     
         5 . The splice mechanism of  claim 4 , wherein the controller is adapted to determine the position of the set of registration marks on the active film along the film path and operate the splice actuator to move the splice roller from the load position to the splice position to align the registration marks on the active film with a known position of registration marks on the second film. 
     
     
         6 . The splice mechanism of  claim 1 , wherein the splice mechanism further includes a vacuum roller positioned between the free position and the splice position of the splice roller such that the splice roller moves circumferentially about the vacuum roller between the free position and the splice position,
 wherein the vacuum roller includes a cavity that is maintained at lower than ambient pressure, and a perforated surface in fluid communication with the cavity, wherein the perforated surface is adapted to retain the film end against the vacuum roller while the adhesive is applied to the film end.   
     
     
         7 . The splice mechanism of  claim 6 , wherein the splice roller is further movable to a load position between the free position and the splice position, and wherein
 the vacuum roller includes an adhesive release surface adjacent the perforated surface; and   the adhesive is an adhesive tape having an adhesive side and a non-adhesive side, wherein the adhesive tape is applied with the adhesive side facing the vacuum roller to span the film end retained against the vacuum roller and the release surface and, when the splice roller is moved from the free position to the load position, the splice roller engages a side of the film that is opposite the adhesive side of the adhesive.   
     
     
         8 . The splice mechanism of  claim 7 , wherein the splice roller is manually movable between the free position and the load position, and
 wherein the splice mechanism includes a splice actuator to move the splice roller between the load position and the splice position.   
     
     
         9 . The splice mechanism of  claim 7 , wherein the adhesive release surface includes a plurality of raised surface features. 
     
     
         10 . The splice mechanism of  claim 9 , wherein the plurality of raised surface features includes cylindrical hemispherical or semi-hemispherical bosses of about 0.2 mm to 5 mm height and 0.2 mm to 5 mm diameter. 
     
     
         11 . The splice mechanism of  claim 7 , wherein the adhesive release surface includes a silicone surface. 
     
     
         12 . The splice mechanism of  claim 1 , wherein the splice mechanism further includes a splice roller shield that moves with the splice roller to allow access to the splice roller in the free position and inhibit access to the splice roller in the splice position. 
     
     
         13 . The splice mechanism of  claim 1 , wherein the film roll holder is movable such that the second film roll is movable to a position previously occupied by the active film roll, thereby becoming the active film roll. 
     
     
         14 . The splice mechanism of  claim 13 , wherein a position occupied by the second film roll is comparatively accessible and the position occupied by the active film roll is comparatively inaccessible. 
     
     
         15 . A packaging assembly comprising:
 a former shoulder; and   a splice mechanism, the splice mechanism including:   a film roll holder for holding an active film roll from which a film is drawn to be fed to a former shoulder and a second film roll having a film for feeding to the former shoulder, wherein the film from the active film roll extends along a film path to the former shoulder and the second film roll is accessible; and   a splice roller against which a film from the second film roll is placed, the film having a film end, the film end having an adhesive, the splice roller being movable between a free position, wherein the film path is unimpeded by the splice roller, and a splice position, wherein the film path is tangential to the splice roller at a splice point on the film path;   wherein the splice mechanism further includes a first pinch drive mechanism locatable along the film path between the active film roll and the former shoulder, the first pinch drive mechanism having a first pinch roller and a second pinch roller positioned such that the first pinch roller and the second pinch roller engage and draw the film from the active film roll at a film speed,   wherein, when the splice roller is in the splice position, the splice roller and the first pinch roller are adjacent each other such that the film of the active film roll and the film of the second film roll is engaged by the splice roller and the first pinch roller, and   wherein, when the splice roller is in the splice position, the first pinch drive mechanism drives the film opposite the film direction.